Lignocellulosic feedstocks comprise mainly of cellulose, hemicelluloses, and lignin. Lignocellulosic feedstocks typically are obtained from renewable resources, such as agriculture, forests, and refineries associated therewith and are not considered to be food sources. In view of these aspects, lignocellulosic feedstocks are considered desirable for the production of biofuels, chemicals, and polymers. In particular, biofuels, such as ethanol and butanol, typically are produced from a lignocellulosic feedstock through a fermentation process. However, given the complex makeup of a lignocellulosic feedstock and the many processes employed to hydrolyze the feedstock, the issue of fermentation inhibitors becomes a problem.
During the hydrolysis of a lignocellulosic feedstock various compounds are formed that can inhibit fermentation and/or enzymatic processes. One class of known fermentation inhibitors is aldehyde compounds, such as furfural and hydroxymethylfurfural (HMF). Such aldehyde compounds can inhibit the fermentation process if not removed from or reduced in concentration in the mixture. A process called overliming is known to reduce concentration of aldehydes and other fermentation and/or enzyme inhibitors in a saccharide-containing composition. In such a process, calcium oxide (i.e., lime) is added to a crude saccharide-containing composition thereby elevating the pH, and elevated temperatures and forceful mixing typically are employed. The composition typically is returned to about neutral pH, and solid gypsum produced as a by-product must be filtered out of the mixture. While an overliming method typically reduces the overall concentration of aldehyde compounds and other fermentation and/or enzyme inhibitors, the process is tedious and typically results in sugar degradation.
Thus, there continues to be a need for providing an improved method of reducing the concentration of fermentation and/or enzyme inhibitors in a saccharide-containing composition, e.g., a composition derived from a lignocellulosic feedstock.
It will be appreciated that this background description has been created by the inventors to aid the reader and is not to be taken as an indication that any of the indicated problems were themselves appreciated in the art. While the described principles can, in some aspects and embodiments, alleviate the problems inherent in other systems, it will be appreciated that the scope of the protected innovation is defined by the attached claims and not by the ability of any disclosed feature to solve any specific problem noted herein.